Split hook fastener

ABSTRACT

The present invention provides a method for forming preferably a unitary polymeric hook fastener comprising a flexible backing, and a multiplicity of spaced hook elements projecting from the upper surface of the unitary backing. The hook elements each comprise a stem portion attached at one end to the backing, and a head portion at the end of the stem portion opposite the backing. The head portion projects in different directions for some adjacent hook members which adjacent hook members each have a flat face which flat faces are mutually opposing in face to face relation.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. Ser. No. 10/745,002, filed Dec.23, 2003, the disclosure of which is herein incorporated by reference.

BACKGROUND AND SUMMARY

The present invention concerns hook fasteners.

BACKGROUND OF THE INVENTION

There are a variety of methods known to form hook materials for hook andloop fasteners. One of the first manufacturing methods for forming hooksinvolved weaving loops of monofilaments into a fibrous or film backingor the like followed by cutting the filament loops to form hooks. Thesemonofilament loops were also heated to form headed structures such asdisclosed in U.S. Pat. Nos. 4,290,174; 3,138,841 or 4,454,183. Thesewoven hooks are generally durable and work well for repeated uses.However, they are generally expensive and coarse to the touch.

For use in disposable garments, diapers and the like, it was generallydesirable to provide hooks that were inexpensive and less abrasive. Forthese uses and the like, the solution was generally the use ofcontinuous extrusion methods that simultaneously formed the backing andthe hook elements, or precursors to the hook elements. With directextrusion molding formation of the hook elements, see for example U.S.Pat. No. 5,315,740, the hook elements must continuously taper from thebacking to the hook tip to allow the hook elements to be pulled from themolding surface. This generally inherently limits the individual hooksto those capable of engaging only in a single direction while alsolimiting the strength of the engaging head portion of the hook element.

An alternative direct molding process is proposed, for example, in U.S.Pat. No. 4,894,060, which permits the formation of hook elements withoutthese limitations. Instead of the hook elements being formed as anegative of a cavity on a molding surface, the basic hook cross-sectionis formed by a profiled extrusion die. The die simultaneously extrudesthe film backing and rib structures. The individual hook elements arethen formed from the ribs by cutting the ribs transversely followed bystretching the extruded strip in the direction of the ribs. The backingelongates but the cut rib sections remain substantially unchanged. Thiscauses the individual cut sections of the ribs to separate each from theother in the direction of elongation forming discrete hook elements.Alternatively, using this same type extrusion process, sections of therib structures can be milled out to form discrete hook elements. Withthe profile extrusion process, the basic hook cross section or profileis only limited by the die shape and hooks can be formed that extend intwo directions and have hook head portions that need not taper to allowextraction from a molding surface. This is extremely advantageous inproviding higher performing and more versatile hook structures. However,there is a desire to further expand the functionality of hook formingprocesses and to create novel hook elements with greater degrees offunctionality and versatility to a variety of fibrous materials.

BRIEF DESCRIPTION OF THE INVENTION

The present invention provides a method for forming preferably a unitarypolymeric hook fastener comprising a flexible backing, and amultiplicity of spaced hook elements projecting from the upper surfaceof the unitary backing. The hook elements each comprise a stem portionattached at one end to the backing, and a head portion at the end of thestem portion opposite the backing. The head portion projects indifferent directions for some adjacent hook members which adjacent hookmembers each have a flat face which flat faces are mutually opposing inface to face relation.

The fastener is preferably made by a novel adaptation of known methodsof making hook fasteners. The preferred method generally includesextruding a thermoplastic resin through a die, forming hook elementsintegrally with a base or base layer. The hook elements have a top hookhead portion and a generally upstanding stem portion joined to theunitary backing. The hook elements are then cut by the methods taught,for example, in U.S. Pat. Nos. 3,266,113; 3,557,413; 4,001,366;4,056,593; 4,189,809 and 4,894,060 or alternatively U.S. Pat. No.6,209,177. The cut locations extend through at least the hook headportion and preferably at least a portion of the stem portion, generallyfrom 1 to 100 percent of the stem portion, preferably 5 to 100 percent.Subsequently, stretching of the backing layer in a direction at an angleto the cuts (generally 90 to 45 degrees) separates the cut portions ofthe hook elements which cut portions then form spaced apart hooks. Thiscreates two or more separated hook head members from a single hookelement wherein the stem portion of the separated hook members havesubstantially flat mutually opposing faces.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be further described with reference to theaccompanying drawings wherein like reference numerals refer to likeparts in the several views, and wherein:

FIG. 1 illustrates a precursor the hook fastener.

FIG. 2 illustrates the structure of a hook fastener after it has beencut down the stem portion of at least some of the hook elements.

FIG. 3 illustrates the FIG. 2 hook fastener after is has been stretchedto separate the cut hook elements.

FIG. 4(a) is an enlarged side view of a cut and separated hook member.

FIG. 4(b) is an enlarged side view of the same hook member of FIG. 4(a)from the uncut side.

FIG. 4(c) is an enlarged top view of the cut and separated hook memberof FIG. 4(a).

FIG. 5(a) is an enlarged side view of an alternative hook member priorto being cut and separated.

FIG. 5(b) is an enlarged side view of an alternative hook member afterbeing cut.

FIG. 5(c) is an enlarged side view of an alternative hook member afterbeing cut and separated.

FIG. 6(a) is an enlarged side view of an alternative hook member priorto being cut and separated.

FIG. 6(b) is an enlarged side view of an alternative hook member afterbeing cut.

FIG. 6(c) is an enlarged side view of an alternative hook member afterbeing cut and separated.

FIG. 7 is a schematic illustration of the method for forming a hookfastener such as shown in FIGS. 1-6.

FIG. 8 is a photomicrograph of a hook fastener such as shown in FIG. 3engaged with a loop fabric.

FIG. 9(a) is an enlarged side view of a cut and separated hook memberthat has an angled cut.

FIG. 9(b) is an enlarged side view of the same hook member of FIG. 9(a)from the uncut side.

FIG. 9(c) is an enlarged top view of the hook member of FIG. 9(a) afterbeing cut and separated.

FIG. 10(a) is an enlarged side view of a cut and separated hook memberthat has been double cut.

FIG. 10(b) is an enlarged top view of the hook member of FIG. 10(a).

FIG. 11 is a photomicrograph of a hook fastener such as shown in FIG. 9.

FIG. 12 is a perspective view of a diaper having a large area tab.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is directed to a method of forming unique hookmembers from a hook strip having upstanding integral hook elements. Theunique hook members have a flat face and an opposing nonflat face, whichflat face, is in opposing face-to-face relationship to a flat face of anadjacent hook member. The nonflat faces can be the same or different onadjacent hook members and generally at least one of the two (or more)opposing hook members has a loop engaging overhanging portion. The hookstrips generally have an integral film backing formed of the same ordifferent thermoplastic resin as the hook elements. Suitable polymericmaterials from which the hook fastener portion can be made includethermoplastic resins comprising polyolefins, e.g. polypropylene andpolyethylene, polyvinyl chloride, polystyrene, nylons, polyester such aspolyethylene terephthalate and the like and copolymers and blendsthereof. Preferably the resin is a polypropylene, polyethylene,polypropylene-polyethylene copolymer or blends thereof. The film backingis generally oriented in at least one direction and has a thickness offrom 25 to 250 μm, or more preferably 50 to 150 μm. The backing of thefastener should be thick enough to allow it to be attached to asubstrate by means such as sonic welding, heat bonding, sewing oradhesives, including pressure-sensitive or hot melt adhesives, and tofirmly anchor the stems and provide resistance to tearing when thefastener is peeled open. However, when a fastener is used on adisposable garment, the backing should not be so thick that it isstiffer than necessary. Generally, the backing has a Gurley stiffness of10 to 2000 as measured by TAPPI test method T543, preferably 10 to 200so as to allow it to be perceived as soft when used either by itself orlaminated to a further carrier backing structure such as a nonwoven,woven or film-type backing, which carrier backing should also besimilarly soft for use in disposable absorbent articles. The optimumbacking thickness will vary depending upon the resin from which the hookfastener portion is made, but will generally be between 20 μm and 1000μm.

A first method such as shown in FIG. 7, of forming hook strips with acontinuous film-like film backing is by extruding a semi-crystallinethermoplastic resin through a die 2 onto a continuously moving moldsurface with cavities. This is generally a roll surface 3 as shown inFIG. 7. The molten resin is extruded or forced into the cavities 12 bypressure, generally by use of a nip 4. In the case of FIG. 7, the nip isformed by the backup roller 5 and the roll 3 but alternatively thepolymer could be nipped between a die face and roll surface or the like.The nip or gap is sufficiently wide such that a coherent film backing 13is also formed over the cavities. The film backing preferably has asmooth surface along the back but could have a textured or roughsurface. The extruded strip 6 has projections or hook elements 8projecting from the backing 13 when the strip is removed from the moldsurface. A vacuum can be used to evacuate the cavities for easierextrusion into the cavities.

The cavities 12 could be in the shape of the final hook elements asdisclosed, for example, in U.S. Pat. Nos. 6,174,476 or 6,540,497. Inthis case, a generally continuously tapered hook is pulled fromcontinuously tapered hook cavities in its final hook form or at least apartially formed hook element. Also, the extruded strip 6 could be a webprovided with only partially formed hook elements or unformed hookelements forming projections. The tip portion of these projections (orthe tips of partially formed hook elements) then could be subsequentlyformed into the desired finished hook elements 9. This would, in apreferred method, be done by deforming the tip portions using heatand/or pressure. The heat and pressure, if both are used, could beapplied sequentially or simultaneously. In a preferred method, heat andpressure is selectively applied to the tip portion in a nip 14. In thiscase, there is provided a nip 14 having at least one first heatedsurface member 15 and at least one second opposing surface member 16.The nip has a gap which gap has a compression zone defined by a firstentry gap width and a second end gap width. The first gap width issubstantially equal to or less than the web first average thickness. Thesecond end gap width is less than the first web thickness and is thesmallest gap width of the nip 14. The final hook strip has formed hookheads 21 on the stems or projections 24 as shown in FIG. 1. The hookelements are then transferred to a cutting station 18 where the hookelements are cut through the hook heads and substantially through thehook stems to the backing or base layer 13. The cut hook elements arethen separated into two or more hook members by stretching or orientingthe backing in at least one direction in the stretching station 19.

In the specific method shown in FIG. 7, a feed stream of preselectedthermoplastic resin is fed by conventional means into an extruder Iwhich melts the resin and moves the heated resin to a die 2. The die 2extrudes the resin as a ribbon of material onto a mold surface 3, e.g.,a cylinder, having an array of mold cavities 12 in the form of elongatedholes, which preferably taper to facilitate removal of the solidifiedresin from the mold cavities. These holes or mold cavities arepreferably in the form of straight (i.e., only one axis in the lengthdirection) cavities. The mold cavities can be connected to a vacuumsystem (not shown) to facilitate resin flow into the mold cavities. Thiscould require a doctor blade or knife to remove excess material extrudedinto the interior face of the mold cylinder. The mold cavities 12preferably terminate in the mold surface having an open end for entry ofthe liquid resin and a closed end. In this case, a vacuum could be usedto at least partially evacuate the mold cavities 12. If the die formsthe nip, the mold surface 3 preferably matches that of the die 2 wherethey are in contact to prevent excess resin being extruded out, e.g.,the die side edges. The mold surface and cavities can be air or watercooled, or the like, prior to stripping the integrally formed backingand upstanding formed stems from the mold surface such as by a stripperroll. This provides a strip or web 6 of a backing or base 13 havingintegrally formed upstanding stems or hooks 8 of thermoplastic material.Alternatively, upstanding stems could be formed on a preformed backingor the like by extrusion molding or other known techniques.

The extruded strip having upstanding stems can optionally be sentthrough a capping station as shown in FIG. 7, wherein the heatedcalender roll 15 contacts a predetermined portion of a distal end of thestems 8 projecting upward from the backing 13 to form a capped head. Theroll temperature will be that which will readily deform the distal endsunder pressure created by the nip in the compression zone 14 withoutcausing resin to stick to the roll 15 surface. The roll 15 surface canbe treated with release coatings resistant to high temperature to allowfor higher temperatures and/or longer contact times between the stemtips or distal ends and the heated roll 15.

Subsequent to the optional capping step, the extruded strip is sentthrough a cutting station wherein the cutter 18 cuts through at least aportion of the hook elements. The cutter 18 can cut using anyconventional means such as reciprocating or rotating blades, lasers, orwater jets. If cutter blades are used, they are generally spaced to makea cut every 150 to 500 μm or preferably every 150 to 300 μm. Generally,at least about 50 percent of the hook elements are cut, preferably atleast 75 percent and most preferably at least 90 percent.

After cutting of the hook element, the base of the strip 6 islongitudinally stretched, at a stretching station 19, at a stretch ratioof at least 2 to 1, and preferably at a stretch ratio of about 4 to 1,e.g., between a first pair of nip rollers 25 and 26 and a second pair ofnip rollers 27 and 28 driven at different surface speeds. Optionally,the strip 6 can also be transversely stretched to provide biaxialorientation to the base or backing. Roller 25 is preferably heated toheat the base prior to stretching, and the roller 27 is preferablychilled to stabilize the stretched base. Stretching causes spacesbetween the cut portions of the hook elements, which then become thehook fastener members. Optionally, the hook strip can be stretched priorto cutting of the hook elements to provide further molecular orientationto the polymer backing.

The hook elements and members are generally of height of from 0.1 mm to2 mm, preferably from about 0.10 to 1.3 mm in height, and morepreferably from about 0.2 to 0.5 mm in height. The hooks have a densityon the backing preferably of from 25 to 500 hooks per square centimeter,and more preferably from about 200 to 500 hooks per square centimeter.With capped hooks, the stem portions have a diameter adjacent the headsof preferably from 0.05 to 0.7 mm, and more preferably from about 0.1 to0.3 mm. The capped heads project radially past the stem portions awayfrom the flat cut face of the hook structure preferably by, on average,about 0.01 to 0.3 mm, and more preferably by, on average, about 0.02 to0.25 mm and have average thicknesses between their outer and innersurfaces (i.e., measured in a direction parallel to the axis of thestems) preferably from about 0.01 to 0.3 mm and more preferably fromabout 0.02 to 0.1 mm. The capped heads have an average diameter (i.e.,measured radially of the axis of the capped heads and the stems) toaverage capped head thickness ratio preferably from 1.5:1 to 12:1, andmore preferably from 2.5:1 to 6:1.

For most hook-and-loop uses, the hooks may be distributed substantiallyuniformly over the entire surface area of the hook strip, usually in asquare, staggered or hexagonal array.

Referring now to, for example, FIGS. 1-3, a hook fastener 20 comprises athin strong flexible film-like backing 22 having generally parallelupper and lower major surfaces 23 and 29, and a multiplicity of spacedhook elements 9 projecting from at least the upper surface 23 of thebacking 22. The backing can have planar surfaces or surface features ascould be desired for tear resistance or reinforcement. The hook elements9 each comprise a stem portion 24 attached at one end to the backing 22and preferably having tapered sections that widen toward the backing 22to increase the hook anchorage and breaking strengths at their junctureswith the backing 22, and a head portion 21 at the end of the stemportion 24 opposite the backing 22.

The hook fastener hook elements following cutting are shown in FIG. 2with cut lines 30. The hook element cut lines can be at any locationalong the stem and the stem could be cut multiple times in the same ordifferent directions. In FIG. 3, the cut hook elements 9 have beenseparated into adjacent mutually opposing hook members 9′ and 9″. Eachhook member has a flat face 36 or 35 facing an opposing adjacent hookmember. The hook head has also been separated into two portions wherethe engaging overhang head portion has been divided so that there is nooverhang on at least the one flat face 35 or 36, but overhang in atleast one other direction on at least some of the hook members. At leastone of the at least two opposing hook members 9′ and 9″, cut from asingle hook element, will have an overhanging or engaging head portion.However, not necessarily all of the hook members will, or need to, havean overhanging or engaging head portion.

The individual hook members will have at least one flat face extendingalong one face of the stem portion and continuing along the headportion. The head portion of at least some of the hook members will havean overhanging portion extending beyond the stem for engaging a loop orfiber or another hook head portion. As shown in FIG. 4(a), theoverhanging portion 37 preferably extends at an angle a from the flatface and extends a distance of from about 0.01 to 0.3 mm, preferably0.02 to 0.25 mm. Tangent lines y-y drawn from a portion of the rim 60 ofthe overhanging portion down towards the base would not be parallel witha flat face. These tangent lines could range from perpendicular to astem flat face or be angled at angle alpha (α) of from 90° to 1°,wherein the angle α is measured from the tangent line y-y to a referenceline x-x drawn from a point on the rim parallel to the flat face.Generally, at least some of the tangent lines a will be at anglesranging from 1 to 89° or 5 to 85°. By this, it is meant that the entireoverhang is not generally parallel with a flat face although someportions of the overhang could to parallel with a flat face. The hookmembers are generally non-rectilinear or asymmetric. Generally, the faceof a given hook member opposite the flat face is not flat but rathercurved or non-smooth. Some of the hook members may not have overhangingportions or only have small overhanging portions. Further, a fastenercan contain both uncut hook elements and hook members in varying ratios.The percentage of cut hook members is at least about 50%, and can be atleast about 90%.

FIG. 4(a) is an enlarged view of the hook members cut from amushroom-type hook element with flat faces 35 and 36 and second faces38, 38′, with continuous overhanging rims 37, 37′. The overhang portion37 extends radially from a preference point 31 at the upper stemportion. The side view FIG. 4(b) shows a portion of the overhang 39substantially perpendicular to the stem flat face 35. The hook headportion 33 is seen in the top view FIG. 4(c).

FIG. 5(a) is an enlarged hook element formed from a continuously taperedJ-type hook element 40 produced by the method such as disclosed in U.S.Pat. Nos. 6,174,476 and 6,540,497. The tip has also been capped in themethod disclosed in FIG. 7 to give a further overhang 45. The mainoverhang 47 is formed in the mold cavity.

In FIG. 5(b), the cut line 41 bisects the hook element 40 which whenseparated as shown in FIG. 5(c) creates two flat faces 46 and 48 withtwo hook members 42 and 49. The hook member 42 has small overhangingportions 45′ extending generally parallel to the backing 22 andgenerally perpendicular to flat face 46. The hook member 49 has a largeoverhanging portion 47 perpendicular to the stem flat face 48 and smalloverhangs 45″ perpendicular with the flat face 48.

FIG. 6(a) is a different version of a continuous taper J-type hookelement 50 produced by a method such as disclosed in U.S. Pat. No.5,755,015. The tip of the stem has also been capped using a method asdisclosed in the FIG. 7 method to give further hook engaging overhangs55. The main hook engaging overhangs 57 and 58 are formed in the moldcavity.

In FIG. 6(b), the cut lines 51 and 51′ bisect the hook element in twolocations. Then the hook element 50 is separated, as shown in FIG. 6(c),into three hook members 50′, 50″ and 50′″. The three hook members allhave at least one flat face. The hook member 50′ has flat face 53 whichfaces flat face 59 on hook member 50″. Hook member 50′″ has flat face 56which faces flat face 58 on hook member 50″. All three hook members haveoverhanging portions 55′ however hook member 50″ could be a stem with nooverhangs.

In FIGS. 9(a and c), the cut line bisects the hook element at a biaswhich when separated, as shown in FIG. 9(a), creates two flat faces 66an 68 with two hook members 64 and 64′. The hook members 64 and 64′ haveoverhanging portions 69 and 69′ extending radially from the flat faces66 and 65, the same as in FIG. 4 but at an oblique angle. This producesnonsymmetrical hook members who oppose each other in face-to-facerelation.

FIGS. 10(a) and 10(b) are enlarged views of multiple hook members 74,74′, 74″ and 74′″ cut from a single mushroom-type hook element with flatfaces and overhanging loop engaging portions 79. The overhang portion 79extends radially away from the flat faces.

In certain applications, it has been discovered that very low hookdensities are desirable. For example, hook densities of less than 100,preferably less than 70 and even less than 50 hooks per squarecentimeter are desirable when used to attach to low loft nonwovens usinga relatively large area flexible hook fastener tab or patch. This lowspacing has been found to increase the hooking efficiency of theindividual hook elements, particularly relative to low cost andotherwise ineffective nonwoven materials not traditionally used as loopproducts. The hook tab or patch is also made flexible by suitableselection of the polymer forming the base layer and/or by the stretchingof the base layer reducing its thickness, to a preferred range of 100 μmto 25 μm. Biaxial orientation can be used to further reduce the hookdensity to the desired range for a large area hook fastener.

A large area fastener when used on a garment type application such asdiapers, see FIG. 12, or the like provides stability between the twoengaged regions. A suitable large area fastener would have a surfacearea of 5 to 100 cm², preferably 20 to 70 cm².

When a large area (oversized) fastener as shown in FIG. 12 is broughtforward or backward for engagement with an outer surface of an article,the oversized fastener may be capable of fastening into any portion ofthe outer surface of the article. With this, the need for a specificattachment region or target attachment zone can be eliminated if thegarment can engage at some minimum level with the fastener. The largerarea also ensures secure closure due to the fasteners size. As such,large area hook fasteners of the invention could potentially eliminatethe need for a separate loop component or other “mating” fastenercomponent on the backing of the garment or article. The increased sizeof the large area fastener also can eliminate the need for secondaryfasteners or bonded areas (such as passive bonds) that may be requiredto stabilize the overlapped regions of the article or garment.

Use of large area fasteners reduces the manufacturing complexity of agarment such as an absorbent article by eliminating the need foradditional bond points or multiple fasteners to stabilize the fasteningsystem of e.g., the front and rear waist regions. The addition of bondpoints or additional fasteners increases the complexity of themanufacturing process.

Specifically, a large area hook fastener, is capable of directlyengaging an outer surface of a diaper provided with a relatively lowloft nonwoven without the need for an expensive loop patch. The largearea flexible hook fastener can also prevent inadvertent opening of theclosure due to the large contact and attachment area creating a morestable garment closure. The oversized hook fastener could also be usedin a prefastened pull-on type garment, due to its large area of contact,making the garment suitably stable for packaging and subsequent use.

EXAMPLE 1

A mechanical fastener hook web (KN-2536, 3M Co., St. Paul, Minn.),similar to that depicted in FIG. 1, having 217 hooks per squarecentimeter, was advanced through a rotary cutting station. The cuttingblades were arranged such that the direction of the cuts was in thecross direction of the web. The downweb (machine direction) spacing ofthe cuts was 254 microns. The cutting depth of the blades was set suchthat the individual hooks were cut down through their length to the baseof the hook. The cut web was then oriented in the machine direction tofurther separate the cut portions of the hooks, with a KARO IVpantograph stretcher (Bruckner GmbH, Siegfred, Germany). A 115 mm by 115mm sample was cut from the web and mounted in the stretcher. The samplewas heated for 60 seconds at 150° C. and then stretched at a rate of100%/sec to a final dimension of approximately 215 mm by 115 mmresulting in a machine direction orientation of 2.0 to 1. Aphotomicrograph perspective view of the resulting hook web, showing theengagement of the cut hook portions with a nonwoven web, is shown inFIG. 8.

EXAMPLE 2

A mechanical fastener hook web (KN-3457, 3M Co., St. Paul, Minn.),similar to that depicted in FIG. 1, having 357 hooks per squarecentimeter, was advanced through a rotary cutting station. The cuttingstation and blades were arranged such that the cuts were at an angle of23 degrees measured from the machine direction of the web. The downweb(machine direction) spacing of the cuts was 254 microns. Aphotomicrograph top view of one of the cut hook elements is shown inFIG. 11.

EXAMPLE 3

A mechanical fastener hook web was extruded and cut as in Example 2. Thecut web was cut a second time by passing the web through the cuttingstation. The cutting station and blades were arranged such that the cutswere made in the machine direction of the web. This resulted in theindividual hook elements being cut twice producing 4 smaller hookelements.

1. A method of forming a hook fastener comprising providing a hookfastener strip having a thermoplastic base layer with integralupstanding hook elements having stem portions and head portions withloop engaging overhangs, cutting at least some of the hook elementsalong the head portion and down to the stem portion substantially to thebase layer and orienting the base layer so as to separate the cut hookelements.
 2. The method of forming a hook fastener of claim 1 whereinthe hook members having a flat face are in opposing face to facerelation with the flat face of another hook member having a flat face.3. The method of forming a hook fastener of claim 1 wherein the filmbacking is oriented.
 4. The method of forming a hook fastener of claim 3wherein the film backing has a thickness of from 25 to 250 μm.
 5. Themethod of forming a hook fastener of claim 3, wherein the film backinghas a thickness of from 50 to 150 μm.
 6. The method of forming a hookfastener of claim 1 wherein the overhanging portions extend 0.01 to 0.3mm.
 7. The method of forming a hook fastener of claim 6 wherein theoverhanging portions extend 0.02 to 0.25 mm.
 8. The method of forming ahook fastener of claim 6 wherein the overhanging portions extend 0.02 to0.2 mm.
 9. The method of forming a hook fastener of claim 1 wherein thehook members have a height of from 0.1 to 2 mm.
 10. The method offorming a hook fastener of claim 1 wherein the hook members and hookelements on the backing have a density of from 25 to 500 per squarecentimeter.
 11. The method of forming a hook fastener of claim 1 whereinat least a portion of the hook engaging portion extends at an angle (α)of from 1° to 90° from a flat face of the hook member.
 12. The method offorming a hook fastener of claim 1 wherein at least a portion of thehook engaging portion extends at an angle (α) of from 1° to 89° from aflat face of the hook member.
 13. The method of forming a hook fastenerof claim 1 wherein at least a portion of the hook engaging portionextends at an angle (α) of from 5 to 85° from a flat face of the hookmember.
 14. The method of forming a hook fastener of claim 1 wherein thehook fastener includes hook elements without flat faces.
 15. The methodof forming a hook fastener of claim 14 wherein the hook members havingflat faces comprise at least 50 percent of the hook structures.
 16. Themethod of forming a hook fastener of claim 15 wherein the hook membershaving flat faces comprise at least 90 percent of the hook structures.